If the patient wants to use a pupil gauge, it is recommended to use a yellow pupil pen. Generally, the light emitted by the pupil pen used by doctors is yellow, that is, the so-called fluorescent lamp, which is similar to sunlight. In medicine, the pupil pen is mainly used to observe the ear hole, nose, nasal cavity, mouth and throat, and to observe whether there are polyp symptoms.
In Ophthalmology, it is mainly to observe the pupil light reflection. After the direct light of the pupil gauge, the doctor can visually observe the parts requiring diagnosis and treatment. The pupil pen with white light will make the doctor have errors due to the reflection of light in the process of observation, so he can't distinguish the disease. The pupil pen with yellow light will simulate the irradiation of sunlight, so that doctors can more accurately observe the lesions or polyps in the nasal cavity, ear holes, mouth and throat. Therefore, it is recommended that patients use the pupil pen gauge with yellow light.